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MikeChino writes "NASA is currently working on a personal aircraft that will put jet packs to shame. The Puffin is an all-electric one-man airplane that could be the start of some new and amazing air travel technology. With two prop electric engines, lithium phosphate batteries and a top speed of almost 300 mph, the vertical take off and landing vehicle was originally designed for covert military insertions because it has a lower heat signature than combustion engines. The Puffin would also be super quiet – 10 times quieter than current low-noise helicopters, and since the engine is electric it has no flight ceiling and can fly up to 9,150 meters high, uninhibited by thin air."

By March, the researchers plan on finishing a one third-size, hover-capable Puffin demonstrator, and in the three months following that they will begin investigating how well it transitions from cruise to hover flight. They are already looking past the Puffin, however.

And that's why we'll never see a full sized vehicle.

The next-generation of this design might incorporate more than just two pairs of prop rotors, so that if one was struck by, say, a bird or gunfire, the aircraft could survive on redundant systems. "We could make it so there's no single point of failure--that's the cool next step," Moore says.

The U.S. government will never allow widespread use of such a craft. The FAA is trying to essentially eliminate community airfields with their regulations and "anti-terrorist" programs. While I'd love to be able to fly to work, it's just not.going.to.happen.

I will believe it when I see it. Batteries that good are a dream. And as far as the nearly 30,000 foot ceiling of this device cold and thin air might be a serious issue. Pilots generally like to breath and being turned into a frozen, air starved corpse is not a goal for most of us. Or are we supposed to think this thing with have a closed cabin with oxygen and heat available? Jesus, we can't even get good batteries for electric bicycles yet.

4 crashes since its inception? That really isn't so bad. You should compare with other military planes. Also at least half of those crashes were due to maintenance, parts failure issues and really have nothing to do with the actual design of the craft. I would say the press did a pretty good job of convincing everyone that the V-22 was a flying deathtrap.....

I don't understand why so many flight related programs are named Icarus. Let's remember what happened in the myth of Icarus: He flew too close to the sun and so he died. I can't tell if such program names are deliberately humorous (hah! Let's see if we can get pilots to fly in something named Icarus! Yeah, I already did that. Let's try to see if we can get them to test out a project named after a flightless bird. Maybe something like a kakapo http://en.wikipedia.org/wiki/Kakapo [wikipedia.org] that sometimes gets hurt from thinking it can fly when it can't), or if they just don't know any other myths related to flight, or if this is a deliberate comment about how many classical claims about "hubris" simply hold humans back from genuine progress. But would it hurt if occasionally a program was named after Horus or after Odin's raven?

Not only does it become difficult to generate lift, but to keep the electric motors cooled. You're always going to have losses in the form of heat and that's generally carried away by the air moving past the motor. An overheated motor when that's what's keeping you from plummeting isn't cool... literally.

The changes this would make to society are too great. The politicians would never allow common people to have that much freedom. No borders, no passports, no way of stopping people from going where they wanted, when they wanted. And that's without assuming any purpose more nefarious than a cheap weekend in Amsterdam.

One asshole with one of these and a pocketful of golf balls could cause carnage in a city centre at rush hour - no way to track or find the culprit afterwards. As long as there's idiots who think throwing rocks off motorway bridges is a fun thing to do, there'll be idiots who'll be delighted to abuse this even worse. Drug dealers, criminals of any kind who want to make a clean getaway (get 10 feet off the ground and nobody's catching you, no matter how fast the police car).

It's not the physics of flight, or fuel capacity, or engine efficiency that will stop us ever getting personal flight vehicles - it's the politicians who will legislate it out of existence for all but the very rich, because whatever rich people want is always all right. And they'll do it in the name of safety, and it'll be for our own good. There'll be a huge furore in the media when the first one crashes and kills someone, and that'll be it done with.

No. Rocket staging has nothing to do with requiring different propulsion systems in different parts of the atmosphere. Rocket staging is about shedding weight and attaining velocity. The more mass you are trying to lift, the more propellant you require. The more propellant you require, the more tankage you need. The more tankage you need, the greater the mass you are trying to lift. Since, after a while, the tanks are mostly empty, why bother continuing to lift them? They aren't needed anymore. Divide the propellant into separate tanks, and when one tank is empty, ditch it.

Now, it's a lot easier to drop the tail end off of a rocket than the forward end, so you drop the engines and the tanks, then switch to a different set of engines. Coincidentally, once the first stage is done you've left the thickest part of the atmosphere, so it makes sense to switch from engines that are efficient on the ground, to those that are efficient in a vacuum.

So, the process isn't "Hey, I'm in a vacuum now, so I need to switch engines.", but "Hey, I'm carrying a lot of dead weight. Let me cut some loose.".